Cutlery – Means for cutting elongate – strand-encircling sheath – Longitudinally
Reexamination Certificate
2000-06-09
2003-01-07
Payer, Hwei-Siu (Department: 3724)
Cutlery
Means for cutting elongate, strand-encircling sheath
Longitudinally
C030S091100, C081S009440
Reexamination Certificate
active
06502310
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of electrical wiring, and, more particularly, to a tool for slitting the outer layer of insulation from a multi-wire cable, such as a Rome cable.
BACKGROUND OF THE INVENTION
Romex cable is a well-known medium for electrical wiring. Typical romex cable comprises three wires, two of which are individually insulated and one of which is non-insulated. The three wires are bundled together in an outer layer of insulation. The configuration of romex cable makes it particularly useful for wiring an AC circuit of the type commonly used in a building, because the three wires needed for such a circuit can be laid together as a single unit (i.e., the two insulated wires can be used for “hot” and “neutral,” and the uninsulated wire can be used for “ground”).
While romex cable provides a convenient means to lay three wires together over the length of a circuit, it is typically necessary at certain points in the circuit for an electrician to “unbundle” the three wires. For example, at the current source or at an outlet that will tap the current from the circuit, the hot, neutral and ground wires must generally be connected to separate terminals. In such situations, it is necessary for the electrician to slit the outer layer of insulation so that he or she can work with each of the three wires individually.
Traditionally, electricians slit multi-wire cables manually by using a pocket knife and a steady hand to slit the outer layer of insulation. Not only is this process physically strenuous, but additionally the electrician must be extremely careful not to strip or cut the individual wires—or cut himself—during the slitting process. Various devices to aid in the slitting process have been proposed. U.S. Pat. No. 5,745,943 (Bagley) proposes a device having a rounded recess with a protruding cutting blade. The multi-wire cable is inserted into the rounded recess and pulled along the cutting blade. However, the rounded recess into which the cable fits cannot be opened to accommodate insertion of the cable. Instead, the electrician must strenuously and/or awkwardly force the cable into the recess and past the cutting blade. Moreover, the device of the Bagley patent provides no means to use leverage to pierce the cable insulation with the cutting blade.
In view of the foregoing, there is a need for a system that overcomes the limitations and drawbacks of the prior art.
SUMMARY OF THE INVENTION
A cable-slitting device in accordance with the invention comprises a jaw into which a cable may be positioned, a claw, and a plier-like apparatus to which the jaw and claw are attached. The plier-like apparatus comprises two members rotatbly joined at a point, so as to permit the ends of the members to open and close with the rotating action of the members. The jaw is attached to an end of one member of the plier-like apparatus, and the claw is attached to the adjacent end of the other member. When the device is in the open position, the jaw and claw are separated sufficiently to permit a cable to be positioned in the jaw without interference from the claw. When the device is in the closed position, the jaw and claw are close together such that the claw is in contact with the outer layer of insulation of a cable that is positioned in the jaw. The device may be pulled along the length of a multi-wire cable such as romex in order to slit the outer layer of insulation.
In order to use the cable-slitting device, the members of the plier-like apparatus are rotated to the open position, thereby separating the jaw and the claw. A cable is then positioned into the jaw. The plier-like apparatus is then transformed to its closed position, thereby bringing the jaw and claw closer together. As the claw is brought closer to the jaw, it comes into contact with the cable's outer layer of insulation at a direction generally perpendicular to the cable, thereby piercing the insulation. Once the insulation is pierced, the user holds the cable-slitting device in one hand and the cable in the other hand. The user then pulls the cable and device in opposite directions, thereby causing the claw to be pulled along the length of the cable, which has the effect of slitting the cable's outer layer of insulation.
In a preferred embodiment of the invention, the jaw has a slanted surface and the claw has a curved inner surface. This configuration aids in permitting the claw to pierce the insulation layer so as not to touch the wires inside the cables.
In a further preferred embodiment, the claw and jaw are provided separate from the plier-like apparatus and are detachably mounted to the plier-like device with screws. This configuration aids in manufacturing by permitting the jaw and claw to be separately manufactured and then attached to a general-purpose plier-like apparatus.
In a further preferred embodiment, the jaw is mounted to the plier like apparatus off to the side of the rotating members, such that, as the cable is pulled through the jaw, it travels alongside the plier-like apparatus without coming into contact with the rotating members.
Other features of the invention are described below.
REFERENCES:
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patent: 5414931 (1995-05-01), Wollermann
patent: 5745943 (1998-05-01), Bagley
patent: 5894617 (1999-04-01), Liou
Greenlee Full Line Catalog,1996, pp. 152-153 and 158-167.
IDEAL General Catalog,ISO 9001, 1997, pp. C-2 through C-10 and C21 through C24.
Klein Tools,Catalog No. 139.1, 1995, pp. 19-31.
Payer Hwei-Siu
Woodcock & Washburn LLP
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